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Processing of 20S pre‐rRNA to 18S ribosomal RNA in yeast requires Rrp10p, an essential non‐ribosomal cytoplasmic protein
Author(s) -
Vanrobays Emmanuel,
Gleizes PierreEmmanuel,
BousquetAntonelli Cécile,
NoaillacDepeyre Jacqueline,
CaizerguesFerrer Michèle,
Gélugne JeanPaul
Publication year - 2001
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/20.15.4204
Subject(s) - biology , ribosomal rna , 18s ribosomal rna , 5.8s ribosomal rna , ribosomal protein , 5s ribosomal rna , 28s ribosomal rna , ribosome , rna , 23s ribosomal rna , microbiology and biotechnology , genetics , gene
Numerous non‐ribosomal trans ‐acting factors involved in pre‐ribosomal RNA processing have been characterized, but none of them is specifically required for the last cytoplasmic steps of 18S rRNA maturation. Here we demonstrate that Rio1p/Rrp10p is such a factor. Previous studies showed that the RIO1 gene is essential for cell viability and conserved from archaebacteria to man. We isolated a RIO1 mutant in a screen for mutations synthetically lethal with a mutant allele of GAR1 , an essential gene required for 18S rRNA production and rRNA pseudouridylation. We show that RIO1 encodes a cytoplasmic non‐ribosomal protein, and that depletion of Rio1p blocks 18S rRNA production leading to 20S pre‐rRNA accumulation. In situ hybridization reveals that, in Rio1p depleted cells, 20S pre‐rRNA localizes in the cytoplasm, demonstrating that its accumulation is not due to an export defect. This strongly suggests that Rio1p is involved in the cytoplasmic cleavage of 20S pre‐rRNA at site D, producing mature 18S rRNA. Thus, Rio1p has been renamed Rrp10p ( r ibosomal R NA p rocessing #10). Rio1p/Rrp10p is the first non‐ribosomal factor characterized specifically required for 20S pre‐rRNA processing.